Fire damage.
We saw in given Exercise that even though the number of fires was falling, the amount of damage due to wildfires has been increasing. Could it be that individual fires are getting bigger? Here's a regression that examines the trend in Acres per Fire, together with some supporting plots:
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a) Does this information help to account for the apparent contradiction between our first analysis that showed decreases in the number of fires and the analysis of Exercise 43 that showed increasing damage? Explain. (Be careful not to claim more than you can support.)
b) What does the residuals plot say about this regression? Discuss the assumptions and conditions for the regression shown here.
Exercise :
Wildfire damage. In an example earlier in the chapter, we saw that the number of wildfires in the United States has been declining. But has the damage done by wildfires also been declining? Here's a scatterplot of the amount of land lost to wildfires (in millions of acres) during the same period, along with a least squares line:
a) Do you think a linear model is appropriate for these data? Explain.
b) Interpret the slope in this context.
c) Can we interpret the intercept? Why or why not?
d) What does the value of say about the size of the residuals? What does it say about the effectiveness of the model?
e) What does mean in this context?